1. Field of the Invention
This invention relates to polymers having aromatic and/or heterocyclic rings as structural elements. More especially, this invention relates to certain thermally stable polymers useful as binding agents for thermo stable propellents, said polymers being thermally stable up to temperatures of at least 200.degree. C. This invention also relates to a method of preparing these polymers.
2. Discussion of the Prior Art
In U.S. Pat. No. 3,755,471, polynitro aromatics are described in which nitrated phenyl rings are joined together. These compounds are crystalline, highly explosive and sensitive to shock. They are, however, still thermally stable at 250.degree. C. These polynitro aromatic compounds are prepared by the reaction of a monochlorotrinitrobenzene (picryl chloride) with a dihalogen trinitrobenzene, the less reactive picryl chloride being employed in excess.
Unfortunately, the compounds of U.S. Pat. No. 3,755,471 are not suitable as binding agents for thermal stable propellents. Unlike nitrocellulose and polyvinyl nitrate, they do not form coherent films and they cannot readily be mixed with plasticizers. Their crystallinity also renders them unsuitable for the preparation of a binding agent.
It therefore becomes desirable to provide thermally stable compositions containing nitro groups which can be formed into polymers which polymers in turn can be formed into coherent films in the presence of plasticizers. More especially, it has become desirable to provide such thermally stable compositions in the form of polymers which can readily be mixed with plasticizers and yet maintain the thermal stability up to temperatures of at least 200.degree. C. Still moreover, it has become desirable to provide such a polymer by an efficient inexpensive process which does not require the use of more than a single organic reactant. These and other objects of this invention are provided by the herein disclosed polymer.